No. 553] 



MENDELIAN HEREDITY 



15 



Black YbEbS 

 Yellow-black ybEiS 

 Ebony YBeoS 

 Sable YBEtS 

 Etc. 



Another combination is represented by certain wing mu- 

 tations. A mutant called miniature appeared and may be 

 represented by m; another mutant appeared, called rudi- 

 mentary, and may be represented by r; and a third form, 

 produced by recombination, was called miniature-rudi- 

 mentary, mr. The symbols for this series would be : 



Wild fly MR 

 Miniature mR 

 Eudimentary Mr 

 Rud.-min. mr 



Later several other mutations in wings also appeared. 

 Six of these may be selected for illustration, viz : Vestigial, 6 

 v g ; Bifid, hi; Arc, a r ; Curved, c v ; Jaunty, j; Balloon, ba. 

 If these are brought into connection with the foregoing 

 the symbols for the wild fly in terms of these factors 

 would be : 



Wild Fly=M, R, V g , Bi, Ar, C, J, B a . 



In order to study the relation of these characters to 

 each other it has become necessary to combine many of 

 them and in order to represent the results some system 

 of symbols must be adopted. Obviously, it would be 

 highly undesirable to be obliged to revise the system each 

 time that any of these new mutations are brought into 

 relation with those that have already been compared. 



It may be asked, why may not the current scheme be 

 retained, since in most cases only two characters are 

 likely to be involved and characters can always be con- 

 trasted in pairs on this scheme? The answer is that more 



• This is the wingless fly of former papers. 



